Vapor Barrier in basement

tthacke

I've seen several posts on many sites for and against vapor barriers in basements. My basement is all below grade, poured walls (not blocks) and is about 13 years old. The studs are to be about 1/2" from the wall, R13 insulation, then vapor barrier, then 1/2" dry wall.

Is the VB okay? If not, what problems will it cause?

Thanks

Bob Mariani

Vapor barrier is needed... R13 Batt insulation is not good for below ground leverl installations. The moisture passing into it will ruin its insulation properties. You must use solid foam (2") insulation. Best to use steel studs, ins will fit into them and then set the next... stud..ins..stud.. very fast and very straight.

Reilley

Please check out this document on basement insulation systems. It's excellent.

http://www.buildingscience.com/docum...lation-systems

I would not recommend using steel studs in the basement. If you really want to use them, limit their use to interior walls.

I'm just finishing up my basement insulation which was installed like this:

1) 1" R5 rigid foam glued/screwed/spray foamed to the concrete (chipped the form ridges off first to get best possible contact)
2) 2x4 SPF studs spaces 2.5" from the foam to allow for R20 batt fibreglass (foam gasket between the bottom plate and floor)
3) R20 fibreglass batt insulation
4) No vapour barrier as the rigid foam serves as a "thermal break" and adding vapour barrier would cause a "double vapour barrier" issue

Happy New Year

Bob Mariani

why would you not use steel studs in any location other than where load bearing situations exist?

Reilley

I didn't mention anything about load bearing situations.

I would not use them on exterior walls because basements have a high probability of getting wet and steel studs will rust.

ponch37300

Reilley...Steel studs are actually galvanized and supposed to resist rust and rot.

Reilley

I don't have any personal experience with steel studs. However I won't argue with Mike Holmes, he seems to know what he's talking about. I pulled my advice from one of his basement episodes.

My car is galv, it's rusting. The water pipes I just removed from my basement were galv too and they were corroded.

Bob Mariani

I have used steel studs for over 18 years. Never a call back. I also have stored steel studs in stock of many years. Never will they rust. BUT... wood will rot with the moisture. Wood warps, rots, splits and is never straight... So really now, what is better for a moist condition.

bjbatlanta

I've been in the drywall trades for over 35 yrs. and metal studs WILL rust! It may take them getting wet for an extended period of time, but they'll rust. Metal studs are for commercial application mainly. I always use wood when framing basements. I would apply the moisture barrier by stapling to the bottom plate for the exterior walls, let it drape to the floor and under the bottom plate of your basement walls, then frame with wood (hand pick it to be sure it's straight). Add your R-13, glue and nail/screw your drywall. You can't glue if the vapor barrier is over the studs. Glue reduces the chance of fasteners popping, reduces the number of fasteners needed, and keeps your walls from rattling. If you have a basement with a "moist condition", that needs to be addressed first. Vapor barrier should only be for the unforseen future problem that COULD develop. You need to start with completely dry walls....

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